The subject invention is directed toward the art of fluid filters and, more particularly to filter devices and systems especially suited for use in conjunction with fluid analyzers.
Typically, sample fluids require particulate filtration or coalescing of small liquid droplets prior to analysis by on-line analyzers. The reason for this requirement is that if particulates are not adequately filtered from sample fluids, damage to the analyzers and/or associated system components can result. Similarly, small liquid droplets, suspended in gas or a second immiscible liquid, can interfere with the accuracy of the analysis and, in some circumstances, cause damage to sensitive analyzers.
The particulate and coalescing filters used to meet the above requirements are found in sample conditioning systems for both on-line process analyzers and environmental analyzers. The need for such filters is rapidly increasing because of increased governmental regulation (EPA and OSHA) pertaining to monitoring and record keeping of environmental releases and employee exposure to process fluids. Also, the need is accelerated because of a trend of increasing use of on-line analysis in lieu of "grab sample" analysis. This results from increasing labor costs and a need for more rapid analysis demanded by current process control strategies.
A variety of filters are currently available for particulate and coalescing filtration of sample fluids. Many of them, however, are less than satisfactory for one or more of a variety of reasons. For example, almost all commercially available units require comparatively extensive associated piping and valving to provide the controls necessary for allowing selective use, bypassing, and filter changing. This associated structure tends to take up a significant amount of space on control panels and the like. Moreover, with many prior art units slight changes in filter types or styles necessitate complete housing changes. Additionally with many of the units it is necessary to disconnect associated piping to effect filter changing.